Automatic electromagnetic automobile door emergency latch



Sept. 7, 1948.

E. l.. PRATT 2,448,619 AUTOMATIC ELECTROMAGNETIC AUTOMOBILE Y DOOR EMERGENCY LATCH Filed Nov. '7, 1946 INVENTOR. Edu/ard L. Pfaff.

ATTCI RN EYB Patented Sept. 7, 1948 Unirse --sTATgEfs PATENT OFFICE AUTOMATIC ELECTROMAGNETIC yAUTOMO- BILE .D.O'OREMERGENGYV LATCH fEdwardLsPratt, Pekin, illl. n ApplicatoifNovember 7, 1946, Serial No. 708,345

(Cl. 18W-82) i3 Claims. l

rlhis invention relates :to latching devices, and more particularly to theprovision of an velegztromagnetically controlled `device for '.latching the doors of an automobile. Y

It frequently happens that people, especially children, fall out of automobiles due .to'theopeningof doors while the automobile is `inmotion, resulting in serious injury or even death.

It is, therefore, an object of this invention ,to provide a latching device for the `doors of .an automobile which automatically Vlatches thecdoors in a closed condition Ywhenever the .automobile is in motion.

A further object is the provision of an electromagnetically controlled device which .automatically latches the doors of a `car as scones `the door starts to open, the device being eectiveas long as the car is in motion.

These and other ,objects ,are attained .bythe novel construction and arrangement .of -parts hereinafter described and illustrated by the accompanying drawings, forming a part hereof and in which:

Figure 1 is an elevational view of the electromagnet controlled latch embodying the invention;

Figure 2 is a view taken on the line 2-2 of Figure l;

Figure 3 is a view taken on the line 3-3 of Figure 1.

Referring to the drawings, the control latch is shown to be mounted on the body post l between the front door 2 and the rear door 3 of a four door automobile. Attached to the post I is a sheet of bre il or other non-conducting and non-magnetic material, upon which is mounted a solenoid I@ of an electro-magnet. A T-shaped stamping, having a cross bar 5 and tongue 6 with a slot l, is secured by a screw 8 through the sheet ll to body post I, the slot allowing upward movement of the tongue 6 and cross bar 5. The tongue 6 can be attached to the armature of the solenoid IB, or the tongue 6 itself may serve as an armature for the solenoid. When the solenoid is energized, the cross bar 5 is raised to engage hooks 9 on the front and rear doors 2 Aing thereonlmobs I6, which engage the front and rear. doors. (SeeFigure 2.) When thedoors are closed, the knobs I6 are raised to raise the terminals I3 from engagement with the post I and when the doors are slightly open, the Yterminals i3 are .forced down by the spring action of strip I2 Ainto engagement with the post I.

Screw I I is connected to one end of thesolenoid liLby a wire Il, and the other end of the solenoid is connected by a wire I to a relay havingcontacts le and an electro-magnet I9, which is vconnected lto a battery 20 by a wire 2|, ,and vto a binding post 22 of a control switch by a 'wire 2I,. v(See Figure l.)

The control switchis in the formof-aplug 2,3, .which replaces the filler plug in a rearaxle or differential housing of an automobile. The kbinding post 22 passes through a bushing 24 of insulating.material, and is connected to aconducting spring 25, .which has a straight portion 2.6 which sattached to a block of corklorthe like, and supports the cork in close proximity to, but not in engagement with, the ring gear 28 of the differential. Positioned in the plug 23 is a cup 2S- of aluminum or other conducting material, having a hole 3l) through which the wire 26 passes.

In operation, the wire 2S does not contact the cup 29 when the car is standing still, and not in motion. But when the car is in motion, the motion of oil or other lubricant in the differential housing acts upon the block 2l to move the Wire 26 into Contact with the cup 29, and thus complete a circuit separate from the solenoid circuit through the plug 23 to ground.

When the car is in motion, at the least opening of a door, one of the contact screws I3 will engage the post I and complete a relayed circuit through the screws I3, strip I2, wire Il, solenoid I8, Wire Il', relay points I8 and wire 2l to the battery. The solenoid I@ is then instantly energized to pull the bar 5 up to engage the hooks 9 and latch the doors to prevent opening thereof. When the car is standing still, the wire 2S does not engage the cup 29, thereby breaking the control circuit, and the doors are unlatched so that they can be freely opened.

It will be seen that the device automatically prevents the opening of doors while the automobile is in motion. The device can obviously be readily designed to control a single door as well as two doors, one door requiring merely the elimination of one knob I6 and a contact screw I3. The device can be readily attached to an autoimoble Without material alterations.

The above description is to be considered as illustrative and not limitative of the invention of which modifications can be made without departing from the spirit and scope of the invention as set forth in the appended claims.

The invention having been described, what is claimed is:

1. In a latching device for the doors of an automobile, hooks on the front and rear doors, a

solenoid mounted on the post of t'he automobile, 10

adjacent the doors of the automobile, -a cross bar adapted to be drawn up to engage the hooks when the solenoid is energized, a spring strip electrically connected to the solenoid and having contact screws adapted to engage the post as a door is opened to ground the solenoid, a control switch having a binding post, a relay winding connecting the binding post of t'he control switch to a battery, a wire spring connected to the bind-- ing post, breaker points controlled by said relay winding connected vto said solenoid, said binding post being held by and insulated from a Iplug adapted to nt in a diierential housing of the automobile, a'cork block connected to the wire spring, said spring adapted to support said cork in close .proximity to, but not in engagement with the ring gear of a diierential in said housing, and a metal cup contacting the plug and having a hole through which the wire spring passes without contacting the cup when the auton mobile is at rest, so that when the automobile is D iin motion, the motion of oil between the ring gear and cork block will .cause the wire spring to move into contact with the cup to ground the wire spring and close an electrical 'circuit through the relay winding to close the breaker points of the solenoid circuit and thereby raise the cross bar to latch the doors.

2. In a latching device for the doors of an automobile, a control switch comprising a plug adapted to replace the ller plug of the diierential housing of an automobile, a terminal supported by and insulated from the plug, a wire spring connected to the terminal, a block of light material connected to the wire spring, said spring adapted to support said block in close proximity to the ring gear of a differential in said housing, and a cup of conducting material in the plug and having a hole through which the wire spring passes without contacting the cup when the automobile is as rest, so that when the automobile is in motion, the motion of oil in the differential housing will cause the block to move to cause the wire spring to engage the cup and close a circuit to ground.

3.In a device for preventing the opening of automobile doors when in motion, hooks on the doors,l a cross bar adapted to engage the hooks to prevent opening of the doors, a solenoid arranged to draw the cross bar into engagement with the hooks, contact screws mounted on a spring strip having knobs engaging the doors so that when the doors are open a circuit to ground is closed through a post associated with the doors, said contact screws being connected through the strip to the solenoid, a normally open switch means for connecting the solenoid to a battery, a control switch comprising a plug adapted to replace the filler plug of a diierential housing, a relay connected between the control switch and battery whereby to close said normally open switch means, a wire spring in the plug and normally insulated therefrom, said wire spring being connected to the means for connecting the solenoid to the battery, a block of light material attached to the spring, said spring adapted to support said block in close proximity to the ring gear of the differential in said housing so that when the automobile is in motion, the motion of oil in the diierential will cause the sprng to close a circuit through the plug to ground, and a sheet of insulating material for mounting th-e solenoid on the post.

EDWARD L. PRATT. 

